Bucannon, out of Washington State and the 27th player taken overall, could be the strong safety in a formidable secondary of Tyrann Mathieu at the other safety spot, with Patrick Peterson and Antonio Cromartie at cornerback.

Niklas, who played at Notre Dame, will be in the mix in the fight for the tight end job, and Martin, out of North Carolina, already has impressed at defensive end, where he could be part of the regular rotation behind Calais Campbell.

Bucannon is trying a bit too hard, Arians said.

"He wants to do everything absolutely perfect," the coach said. "Even Tyrann said , 'Man, just play.' You can't play perfect all the time. He doesn't want to make a mistake and you love that about him. ... Anytime that you're the No. 1 pick, there's a certain amount of pressure that comes with it also you should have all the potential to handle that pressure."

Buccanon said the biggest challenge has been mentally.

"It's a big mental jump is the biggest thing from college to the NFL," he said, "At the same time, if you put in that work and you use the resources that you have and continue to get better and better each day. I'm not there yet, but I'm going to get there."

Nicklas has yet to practice, still recovering from hernia surgery. He was joined on the sideline by fifth-round draft pick John Brown. The speedy wide receiver, Arizona's second third-round pick, has hamstring tightness.

Martin has impressed Arians, even though the coaches have had to slow the player down a bit, since the workouts are in shorts.

"We've got to slow him down. I'd rather say 'woah' than 'sic 'em,'" Arian said. "He's around the quarterback way too much, but he's doing a heck of a job. He's a little more powerful than I thought he'd be. "

Martin said he's been practicing with the first team and is learning from the likes of Campbell and Darnell Dockett.

"I'm coming here expecting to play," Martin said. "Whatever team I was going to go I was expecting to contribute right away. So if I get to play early, it's just what I expected to do the whole time."

Under Arians' system, the team is divided in half, each practicing on a separate field. That greatly increases the attention the youngsters get. Of course in rookie camp, they get all the attention. He credited the latest collective bargaining agreement that allows more practice time for the youngsters.

"We can get so many more reps," Arians said, "and get them taught so they can play fast. It's their skill set versus another skill set. I don't really care, we're going to play the best guy. I don't care how you got here, when you got here, if you're the best guy you're going to play."